Hate to say it, but I’m having a very similar issue. Updated H9 Control & H9s. Same Galaxy8 phone. Latest version (as if there was a choice beyond 2 postponements). Except I’m experiencing ‘numbers-no-letters’ in saved names / renaming dialog(ue)s. Full keyboard is available. But it will only ‘print’ numbers.
Alphabet letters all become essentially backspaces. Landscape mode is not an option, as the save / rename popup disappears. And I mean disappears … gone when returning back to portrait orientation.